Tube bending apparatus



A ril 2, 1963 N. E. RICE 3,083,753

TUBE BENDING APPARATUS Filed July 14, 1960 '7 Sheets-Sheet l INVENTOR. N NeLsonEZRwe BY 9M0, W8W

ATTORNEYS A ril 2, 1963 N. E. RICE 3,083,753

TUBE BENDING APPARATUS Filed July 14, 1960 '7 Sheets-Sheet 2 Fig.2

I :I l

INVENTOR. Nels011/E.Rice

BY 9m, Wk M ATTORNEYS April 2, 1963 N. E. RICE 3,083,753

TUBE BENDING APPARATUS Filed July 14, 1960 Sheets-Sheet 5 Fig.3

IINVENTOR.

NelsonElRiae BY $MW-8 M ATTORNEYS April 2, 1963 N. E. RlCE TUBE BENDING APPARATUS 7 Sheets-Sheet 4 Filed July 14, 1960 I INVENI OR. Nelson E. Rwe

ATTORNEYS April 2, 1963 N. E. RICE TUBE BENDING APPARATUS 7 Sheets-Sheet 5 Filed July 14, 1960 INVENTOR. Nelson E. Rwe

ATTORNEYS April 2, 1963 N. E. RICE 3,033,753

TUBE BENDING APPARATUS Filed July 14, 1960 7 Sheets-Sheet 7 Fig: 21

' INVENTOR.

Nel/son E. Rice a i waaqk W ATTORNEYS United States Patent Ofi Patented Apr. 2:, 1963 3,083,753 TUBE BENDING APPARATUS Nelson E. Rice, North Canton, Ohio, "assignor to Macomher, Incorporated, Canton, 'Ohio a corporation or Ohio Filed Juiy 14, 1969, Ser. No. 42,838 15 Claims. ((11. 153-48) members, a zig-zag or reversely bent .web. member is welded at alternate bends to top and bottom chordmemtbers to :form the fabricated joist or the like, these points of welding being coincident with the panel points of the joist or other fabricated structural member.

This necessitates uniform bending of the web member throughout its entire length. Under :present practice, this bending of the web members is performed manually, whichis a slow, tedious. and expensive operation. As such fabricated structural members are madein :lengths up to sixty feet, the web memberis very difficult to bandle after the first few bends have been formed therein, and it is very difficult to maintain uniform bends :throughout the length of the web member.

Furthermore, tubes have now generally been substituted for solid rods or bars in the manufacture of such reversely bent web members, in order to obtaintthe advantages of decreased weight and increased strength. With the vpresent practice of manual bending, it is difiicult to properly bend the tubes without collapsing them -at the points where theyare bent.

-Also, owing to the inherent resilience in steel tubing and the like there is a natural tendency for the same to spring back slightly after being bent to zig-zag form as required for web members for fabricated joists and the like. This makes it difiicult toproperly locate the bends at panel points of the joist.

It is, therefore, an object of the invention to provide apparatus for bending tubular web members which overcomes the disadvantages tand 'difiiculties of present practice.

Another object of the invention is to provide apparatus for continuously bending longitudinally moving steel tubing as it passes outof the tube mill, to form reversely bent tubular web members of any desired or necessary length.

A further object of the invention is to provide apparatus for forming uniformly spaced reverse V-shape bends in a tubeand subsequently setting each end to prevent any spring back, so as to maintain uniform spacing in the finished web member to properly locate the bends at panelpoints in the joist or the like.

A still further object is to provide apparatus for reversely bending tubing without undesirable collapsing of the tube at the bends.

Another object of the invention is to provide apparatus'of the character referred to which bends the tube or bar under tension during the bending operation so that it is stretched as it is bent, thus tending to set the, V- shape bends in the tube or bar.

A further object of the invention is to provide such apparatus in which the previously bent tube-or bar is further stretched to slightly beyond the yield point of the metal, during the setting operation, so. asto positive- 1y set the V-shape bends and prevent any spring-back.

It is also an object of the invention to provide'apparaice .2 tus comprising bending dies and setting dies, with fluid cylinder means for operating the dies, and trip switches operated by the continuously moving tube for automatically 'op'erating solenoid valves for actuating theflu-id cyltinder me'ans to continuously form reversely bent tubular -.web members for fabricating steel structural members.

Theabo've an'd other objects, apparent from the drawings and following description, may be attained, the above described ditficulties overcome and the advantages and results obtained bythe apparatus, construction, arrangeizme'nt a'nd combinations, subcombinations and parts which :comprise thepresent invention, a preferred embodiment of which, illustrative of the best modein which applircant has contemplated applying the principle, being set forth in det'ail in the following description and illustrated :in the, accompanying drawings.

:Iu general'te'rms theinvention may be briefly described as comprising .jan appar'atus located at the exit end of a tubemill for continuously reversely bending the mov- 1ing-tube asitpassesoutof the-tube mill, to form a tu- Ibularwebmemberbent reversely to provide a successive :seriesof oppositely"directedbends or Vs.

The apparatus includes a frame having three slide emem'bersiimounte'd thereon for horizontal sliding movement relative tothe frame and to each other, pneumatic cylinder meansfonrmoving said slide members horizontally, clamping dietmea'ns on the first slide-member, verticallymova'ble.bending sdiemeans on the second slide member and two upper and one lower holding and setting die rneans on the third slidetmember.

:Hydraulic..cylindewoperated toggle levers are provided for operating the clamping die means for clamping a :portionofthe movingtube thereon so that the first slide member willtmove in unison with the moving tube. A "hydraulic cylinder is carried upon the second slide mem- ?ber for. moving the bendingdie thereon transversely of the path of the moving'tube to form V-shape bends in the tube at uniformly spacedin'tervals, between the clamping die :meatns on the first slide member and the first of the upper holding andssetting die means on the third slide member.

Other hydraulic cylinder-operated toggle levers are provided uponthe third slidemerriber for operating the holding andsettingtdie means'thereon for clamping and-holding a previously "bent portion of the tube therein to set the bends 'in thettube.

The clamping die means upon the first slide member comprisesapair of die blocks movabletoward and from each-other, havingzin their-opposed faces straight grooves of 'roundedcross section to receive and clamp a portion of the moving tube therebetween.

For the purpose of preventing the tube from being deformed or'pressed out-of-round at this point, the groove in one of :the'clamping members, preferably the lower member, is completely semi-circular in crosssection so as to support the sides .of the tube against distortion underpressureiby the other member.

.A. circular bending die is mounted upon the first slide member beyond the clamping die means thereon, and provided with a circular groove receiving the underside of the tube. When the vertically movable bending die onkthe second :slide *member is moved downwardly to form a V-"shape ibend therein, reverse bends are formed in theftubeio'r bar as it is bentdown over this bending die on the first slide member and over the first upper holding and setting die on the third slide member.

'Duringth'is bending operation, the tube or bar is in tensionidue to the resistance of the pneumatic cylinders to. lateral movement of the'first and third slide members toward the central slide member. The tube or bar is thus stretched as it is bent, tending to set the bend therein.

Each of the upper setting die means on the third slide member comprises a die block having a groove therein shaped to fit the corresponding bend in the tube, said die blocks being movable vertically upward away from the path of the moving tube by means of hydraulic cylinder-operated toggle levers.

Each of the upper holding and setting die means also includes a circular die with circular grooves therein for engaging the undersides of the corresponding bends in the tubes and means is provided for moving the same downwardly and 'baclewardly away from the path of the moving tube.

This means preferably comprises cam plates having downwardly and rearwardly inclined arcuate cam slots therein engaged by rollers upon the blocks, upon which said circular die members are mounted.

The lower holding and setting die means on the third slide member is of a similar construction excepting that the parts are reversed. The'die block having the groove setting the bend in the tube is movable downward away from the tube by means of hydraulic cylinder-operated toggle levers and the circular die block with circular groove therein is movable upward and backward by means of cam plates having upwardly and rearwardly disposed arcuate cam slots therein engaged by rollers upon the block, upon which the circular die is mounted.

The lower setting die is so located with relation to the upper setting dies or the third slide member that the previously bent portion of the tube or bar is further stretched during the setting operation, the metal being stretched slightly beyond the yield point, so that the bends are positively set.

The operation of the apparatus is continuous, the various pneumatic and hydraulic cylinders which operate the slide members and the several die members being automatically actuated at predetermined times through the operation of valves controlled by microswitches actuated by the moving tube to form and set successive V-shape bends in the continuously moving tube as it is received from the tube mill and progressed through the machine.

Having thus briefly described the invention, reference is now made to the accompanying drawings illustrating a preferred embodiment of the invention, in which;

FIG. 1 is a side elevation of the improved tube bending apparatus to which the invention pertains, showing the bending mechanism in position to form the bend in a tube and showing a previously formed bend clamped in the holding and setting die means, the horizontally movable slide members being separated from. each other upon the frame;

FIG. 2 is a view similar to FIG. 1 showing cylinderoperating bending dies on the second slide member rolled to form the next succeeding bend in the tube, the slide members being located closely adjacent to each other;

FIG. 3 is an enlarged end view of the apparatus looking toward the right hand end thereof as shown in FIG. 1;

FIG. 4 is an enlarged transverse vertical sectional View through the apparatus taken as on the line 4-4, FIG. 1;

FIG. 5 is an enlarged fragmentary transverse sectional view showing the clamping die means on the first slide member and the hydraulic cylinder-operated toggle lever for actuating the same, taken on the line 55, FIG. 1;

FIG. 6 is an enlarged perspective view of one of the cam-operated die blocks on the third slide member;

FIG. 7 is an enlarged transverse vertical sectional view through the second slide member showing the vertically movable cylinder-operated bending die, taken on the line 7-7, FIG. 1;

FIG. 8 is an enlarged transverse sectional view through the apparatus showing the first slide member and the clamping bending die means thereon and the cylinderoperated toggle levers for actuating the same, taken on the line '88, FIG. 1;

FIG. 9 is an enlarged fragmentary horizontal sectional view through one end portion of the apparatus and 4 through the first slide member, taken on the line 99, FIG. 1;

FIG. 10 is an enlarged fragmentary horizontal sectional view through the second slide member, taken on the line 10-10, FIG. 1;

FIG. 11 is an enlarged horizontal sectional view through the third slide member, taken on the line I111, FIG. 1;

FIG. 12 is an enlarged fragmentary vertical sectional view through the upper guide means for the slide members, taken as on the line 1212, FIG. 1;

FIG. 13 is a similar section through the lower guide means for the slide members, taken as on the line ISI3, FIG. 1;

FIG. 14 is an enlarged fragmentary longitudinal sectional view showing the roller bearing for one of the sliding members, taken on the line 14-14, FIG. 13;

FIG. 15 is an enlarged fragmentary sectional elevation of the clamping die means on the first sliding member;

FIG. 16 is an enlarged fragmentary sectional elevation of the upper member of the first upper holding and setting die means on the third slide member;

FIG. 17 is an enlarged fragmentary sectional elevation of the lower member of the lower holding and setting die means on the third slide member;

IG. 18 is an enlarged fragmentary sectional elevation of the upper member of the second upper holding and setting die means;

FIG. 19 is an electrical wiring diagram showing the various switches which control the continuous automatic operation of the apparatus;

FIG. 20 is a diagrammatic view of the pneumatic system including the pneumatic cylinders which operate the slide members and the valves which actuate the cylinders; and

FIG. 21 is a diagrammatic view of the hydraulic system showing the hydraulic cylinders which operate the clamping die means, the bending die means and the holding and setting die means and the solenoid-operated valves which actuate the same.

Referring now more particularly to the embodiment of the invention illustrated in the drawings, in which similar numerals refer to similar parts throughout, the apparatus as best shown in FIGS. 1 and 2, is mounted upon a frame comprising generally the base member 1, the vertically disposed end members 2 and 3 and the upper member 4, each of which may be in the form of H-beams, wide flange I-beams, or the like.

Three horizontally movable slide members, indicated generally at 5, 6 and 7, are mounted for relative movement toward and from each other upon the frame. For this purpose, longitudinally disposed ways 8 and 9 are mounted upon the top of the base member 1 and on the underside of the top member 4, respectively.

Bearing members 10 and 11 are mounted upon the lower and upper ends respectively of the slide members 5, 6 and 7 for rolling engagement upon the ways 8 and F, respectively. These bearing members, which are illustrated in FIGS. 12, 13 and 14, have anti-friction rollers 12 which travel in a closed circuit and engage the ways 8 and 9 respectively.

Since these bearing members are of usual and well known construction, and in themselves form no part of the present invention excepting to provide anti-friction means for moving the slide members 5, 6 and 7 upon the ways 8 and 9, it should be understood that any other suitable anti-friction means may be substituted therefor.

In actual practice, the apparatus is positioned with the end member 2 of the frame adjacent to the discharge end of the tube mill, as indicated at 13 in FIGS. 1 and 2, and is so disposed that the tube 14, as it emerges from the tube mill, will move longitudinally through the apparatus in the direction of the arrows shown in FIGS. 1 and 2.

A tube guide 15 may be mounted upon the end frame member 2, through which the continuously moving tube 14 is guided to the clamping die means upon the first slide member 5, as will be later described in detail.

The clamping die means comprises the upper stationary die 16 and the lower movable die '17. The upper die 16 is attached to the stationary die holder 18, as by the cap screws 19. The die holder '18 is rigidly attached to the first slide member 5 as by the cap screws 20.

A straight groove 21, disposed longitudinally of the path of the moving tube 14 and arcuate in cross section, is formed in the lower edge of the stationary clamping die 16, as best shown in FIG. 15. The lower or movable clamping die 17 is attached to the movable die holder 22 as by cap screws 23.

The die holder 22 is vertically slidably mounted in the gibs 24 upon the slide rnemberS. A straight groove 25 is formed in the upper surface of the movable die 17, as best shown in FIG. 15, thisgroove being of complete semi-circular shape in cross section so as to support the tube entirely around the under half-of its center in order to prevent the tube from being distorted out-of-round when clamped between the dies 16 and 17.

A die 26 is mounted upon the slide member 5 just beyond the-clamping die-and is preferably movable vertically upon the slide member 5 toward and "from the underside of the tube 14. The die 26 is circularand,

as best shown in FIGS. 8 and 9, is provided with an annular groove .27 adapted to receive the underside of the tube 14.

This die is mounted upon the die 'holder 28 which is vertically movable in the gibs 24' and 29'fixed upon the slide member 5. The circular die 26 is adjustably mounted upon the vertically movable die holder 28, as by the bolts 3%, whereby itmay be rotatably adjusted from time to time as the portion of the-groove 27 therein becomes worn. A back-up insert-block 31 is mounted upon the vertically movable die holder 28 and provided with the arcuate upper surface 32 which receives the lower side of the circular die 26.

For the purpose of vertically moving the lower clamping die 17 and the-circular die 26 toward and from the path of the moving tube 14, two pairs of toggle levers are provided, as indicated generally at 33 and 34 respectively.

The toggle levers 33 are pivotally connected at their upper ends to the vertically movable die holder 22, as indicated at 35, and at their lower ends tothe slide block 36 vertically adjustable within the gibs-37 upon the slide member 5 and adapted to be adjusted by the adjusting screw 38. The toggle levers 33 and 34 are pivotally connected to the pin 3? which is mounted perpendicularly upon the end of the piston rod '40 of the hydraulic cylinder 41, as shown inFIG. 8.

In order to provide for a slight lag in the opening of the clamping dies 16- 17 until after the circular die 26 has started to move downward away from the tube 14, the inner ends-of the toggle levers 33 are provided with elongated slots 42 which receive the pin 39 carried by the piston rod 40, as shown in FIG. '5.

A vertically disposed hydraulic cylinder 43 is mounted upon an extension 44 at the top of the second slide member 6, as best shown in FIGS. 1, 2 and 7. This is the main bending cylinder of the machine which operates the bending die which forms V-shape bends in the tube as will be later described.

The piston rod 45 is disposed downwardly from the cylinder 43 and, as best shown in FIG. 7, is threaded, as indicated at 46, into the verticallyslidable die'block 47 slidably mounted within the vertical gibs 48 :upon the slide member 6. i

The circular bending die 49 provided with annular groove 50 therein is mounted upon the die block -47. In order that the die 49 may' be'rotatably adjusted to compensate for wear in the-groove 50, it is mounted upon the block 47 by the bolt 51. A back-up insert block 52 6 is mounted upon the die block 47 between the bending die 49 and the overhanging shoulder -53 of the block 47.

For the purpose of limiting the downward movement of the bending die 49, a stop block 54 is mounted upon the slide member 6at a point near the lower end thereof. In order to provide for forming bends of various depths in the tube, the stop block 54 is shown as vertically adjustably-mounted in the gibs 48, and an adjusting screw '55, threaded through the back-up block 56, which is rigidly attached to the slide member '6, contacts the lower surface of the stop block 54, whereby the stop block maybe vertically adjusted inthe gibs.

Spaced pairs of vertically disposed guide rods 57 are carried by the slide member6 on opposite sides of the gibs48. The guide rods 57 are connected at their upper and lower ends to brackets 58 rigidly mounted uponthe slide member 6. The guide rods 57 are so spaced as to guide the tube'14 therebetweenduring the bending 0peration.

The third slide member, indicated generally at 7, is equipped with holding and setting die means for setting the bends in the tube immediately subsequent to the forming of the bends by the bending die mechanism on the slide '6. This holding and settingdie means comprises two similar iupper 'settingdie means spaced apart horizontally in the longitudinal path of the tube and indicated generally at 59 and 59,and lower setting die means indicated generally 'at 60 and located midway between and at a point below the upper setting die means 59 and 59.

The lower setting die means 60 is so loc'ated relative to the upper setting die means 59 and 59" that the bent portion of the tube or rod will be further stretched in the setting operation, stretchin the metal. slightly beyond the yield point so as to positively set the bends therein.

The first upper holding andsetting 'die means, indicated generally at 59, includes the upper 'die61, shown in detail in FIG. 16, and the lower circular die 62. The upper die '61 has a groove 63 in 'its lower surface which is arcuate in cross section to conform to the curvature of the tube.

The groove 63 has the straight portion 64 extending from the 'left sideof the die to the center thereof and terminating in the downwardly curved portion 65 conforming to the bend in the tube which. has previously been made around the circular die 26.

The die 61 is rigidly connected, as 'byscrew 66, to the back-up 'block 67 which is vertically slidably mounted within the ,gibs 68 upon the slide member 7. Toggle levers '69 are pivotally connected at'their lower ends as at 70 to the back-up block67 and are pivotally connected at their upper ends as at 71 to a block '72mounted in the gibs-68.

The block 72may be vertically adjusted in the gibs 68 by means 'of an adjusting screw 73 located through an internally threaded flange 74 rigidly mounted upon the slide member 7, lock nuts 75 being providedithereon for holding the block 72 in adjusted position.

The toggle levers 69 are pivotally connected at their inner ends to a pin 76 carried by the piston rod 77 of a hydraulic cylinder 78. This hydraulic cylinder is indicated on the diagrammatic view of the hydraulic system shown in FIG. Zland is exactly like the hydraulic cylinder 78 for the second upper holding and setting die greanls 59 shown in FIG. 3 and hereinafter described in etai The circular die 62 is provided with an annular groove, such as the dies 26 and 49 above described, and is rotatably adjustably mounted upon the die block 79 by the screw 80. A back-up insert block 81 is mounted on the die 'block79 contacting the undersurface of the circular die '62.

The die block 79 is adapted to be moved downwardly and rearwardly to move the die 62 out of the path 'of the moving tube. For this purpose rollers 82 are pro- 7 vided on the die block 79 for engagement in cam slots in the cam plates 83.

The rollers 32, cam plates 83 and cam slots therein are identical with the rollers 82', cam plates 83 and cam slots 84 for the second upper holding and setting die means 59 as illustrated in FIG. 3.

The second upper holding and feeding die means, indicated generally at 59', includes the upper die 61, shown in detail in MG. 18, and the lower circular die 62'. The upper die 61 has an arcuate groove 63' in its lower surface, which is arcuate in cross section to conform to the curvature of the tube and curved longitudinally to conform to the bend in the tube which has previously been made around the circular die 62 during the bending operation.

The die 61 is rigidly connected, as by screws 66, to the back-up block 67' which is vertically slidably mounted within the gibs 68 upon the slide member 7. Toggle levers 69 are pivotally connected at their lower ends, as at 70, to the back-up block 67 and are pivotally connected at their upper ends, as at '71, to a block 72' mounted in the gibs 68.

The block 72 may be vertically adjusted in the gibs 63' by means of an adjusting screw 73 located through an internally threaded flange 74' rigidly mounted upon the slide member 7, lock nuts 75 being provided therefor for holding the block 72' in adjusted position.

The toggle levers 69 are connected at their inner ends to a pin 76' carried by the piston rod 77 of a hydraulic cylinder78'. This hydraulic cylinder is indicated on the diagrammatic view of the hydraulic system shown in FIG. 21, and the hydraulic cylinder 78 for the first upper holding and'setting die means 59, above referred to, is of exactly the same construction and arrangement.

The circular die 62 is provided with an annular groove 62a and is rotatably adjustably mounted upon the die block '79 by the screw 80'. A back-up insert block 81 is mounted on the die block 79 contacting the undersurface of the circular die 62.

The die block 79 is adapted to be moved downwardly and rearwardly to move the die 62 out of the path of the moving tube. For this purpose, rollers 32 are provided on the die block 79 for engagement in the cam slots 84 in the cam plates 83.

In order to move the die block 79 downwardly and rearwardly so that the rollers 82' thereon will travel through the cam slots 84 in the cam plates 83', the piston rod 86' of the cylinder 85 is pivotally connected as at 87' to one end of a lever 88 which is fulcrumed intermediate its ends upon the slide member 7, as indicated at 89.

The other end of the lever 88 is bifurcated and pivotally connected, as at 8%, to the depending arm 90 of the die block 79'. This construction is shown in FIG. 3. The die block 7% of the holding and setting die means 59 is similarly operated, the depending arm 90 thereof being pivotally connected as at 89 to the adjacent end of a lever 88, identical with the lever 88, which is connected at 37 to the piston rod 86 of the hydraulic cylinder 85 above referred to, as shown in FIG. 21.

The lower holding and setting die means, indicated generally at 60, is mounted for vertical adjustment upon the slide member 7 in order to provide for the setting of bends of various depth which may be formed in the tube by the bending dies.

.For this purpose, the vertical central portion of the slide member 7 is cut out as shown at 91 in FIGS. 1, 2 and 4, and the holding and setting die means, indicated generally at 60, is carried by a slide 92. vertically slidable within the gibs '93 at opposite sides of the cut-out 91.

A hydraulic cylinder 94 is mounted upon the extension 95 at the upper end of the slide member 7 and the piston rod 6 thereof is connected to the slide 92. It should be understood that the hydraulic cylinder 94 is not located in the hydraulic system shown in FIG. 21 and is not automatically controlled, but may be manually controlled for the purpose of vertically adjusting the entire holding and setting die mechanism at in order to vertically adjust the same to set bends of various depths in the tube.

The holding and setting die mechanism, indicated generally at 60, carried by the slide 92, is the same as the upper holding and setting die mechanism indicated generally at 59 and 59 and described in detail above, with the exception that the parts are reversed.

This mechanism. as best shown in FIG. 4, includes the lower die 61, shown in detail in FIG. 17, and the upper circular die 62" having the annular groove 62b therein. The lower die 61" has a groove 63" in its upper surface which is arcuate in cross section and curved to conform to the bend in the tube previously formed by the bending die &9.

The die 61" is rigidly connected, as by screws 66", to the back-up block 67 slidably mounted within the gibs -68 upon the slide 92. Toggle levers 69 are pivotally connected at their upper ends, as at 70", to the backup block 67 and are pivotally connected at their lower ends, as at 71", to a block 72 mounted in the gibs 68'.

The block 72 may be vertically adjusted in the gibs 68 by means of an adjusting screw 73 located through the internally threaded flange 74" rigidly mounted upon the slide 92, lock nuts 75" being provided thereon for holding the block 72" in adjusted position.

The toggle levers 69 are pivotally connected at their inner ends to a pin 76 carried by the piston rod 77 of the hydraulic cylinder 78". The circular die block 62 is rotatably adjustably mounted upon the die block 79" by a screw 80". A back-up insert block 81" is mounted on the die block 79" for contacting the upper surface of the circular die 62".

The die block 79 is identically the same as the die blocks W and 79 above described excepting that it is inverted. This block is adapted to be moved upwardly and rearwardly out of the path of the moving tube in the same manner that the die blocks 79 and '79 are moved downwardly and rearwardly out of the path of the tube. For this purpose, rollers 82" are provided on opposite sides of the die block '79 for engagement in the cam slots 84" in the cam plates 83".

For the purpose of moving the die block 79" through the cam slots in the cam plates, a hydraulic cylinder $5 is provided which is similar to the cylinders 35 and 85' excepting that it is inverted. The piston rod 85" of this cylinder is pivotally connected at 87 to the adjacent end of the lever 88" fulcrumed intermediate its ends as indicated at 8?". The other end of the lever 88 is bifurcated and pivotally connected as at 89a" to the upwardly disposed arm Ml" of the die block 79.

Spaced pairs of guide rods 57', similar to the guide rods 5'7 on the slide member 6, are located at opposite sides of the slide member 7 for guiding the tube therethrough. These guide rods are connected at their upper and lower ends to the brackets 58' rigidly attached to the slide member 7.

For the purpose of separating the slide members 5, 6

and 7 after each bending operation, a plurality of pneumatic cylinders are provided as shown in FFGS. 1, 2, 9, l0 and 20. The cylinder 1% is rigidly attached to the frame of the apparatus at the left hand end thereof, as viewed in FIGS. 1 and 2, and the piston rod 101 thereof is connected at Hi2 to the adjacent side of the first slide member 5.

The pneumatic cylinder 103 is mounted upon the back of the slide member 5 and the piston rod 104- thereof is connected at 105 to the second slide member 6. The cylinder 107 is mounted upon the back of the slide member 6 and the piston rod 1% thereof is connected at 109 to the third slide member 7.

Reference is now made to the hydraulic system shown diagrammatically in FIG. 21. The motor drives the pump 116 having inlet pipe 117 leading from the oil reservoir 118, a strainer 119 preferably being provided thereon.

The discharge or pressure pipe 120 leads from the discharge side of the pump to the four-way solenoid-operated valve 121. A check valve 122 is located in the pipe 120 to permit flow therethrough only in the direction of the arrow, and a relief valve 123 is located in the pipe 120 between the pump and the check valve 122.

An oil return pipe 124 leads from the four-way valve 121 to the reservoir 118. The four-way valve 121 is connected by the pipe 125 with a pipe .126 which leads to one end of the cylinder 41 and to thecorresponding end of the cylinder 78' and which is connected by pipes 127 and 128 to the corresponding ends of the cylinders 78 and 78".

The other end of the cylinder 41 is connected to the four-way valve 121 'by a pipe l29and the other ends of the cylinders 78, 78' and 78" communicate with the pipe 130 which communicates with the four-way valve 121 through the pipe 13-1.

Pipe 132 communicates with the pump discharge pipe 120 and is provided witha check valve .133 which permits flow only in the direction of the arrow. The pipe 132 is connected to the solenoid-operated four-way valve 134 and a return pipe 135 leads from the valve 134 to the reservoir 118.

The pipe 136 leads from the valve 134 to one .end of the main bending cylinder 43 and the other-end of the cylinder 43 is connected to the valve 134 by pipe137. A usual construction of sequence valve 138 is located in the pipe 126, and the pipe 139 is connected to the sequence valve and leads to one end of each :of the cylinders 85, 85 and 85". The other endsof these three cylinders are connected to the four-way valve 121 through the .pipes 131 .and 129. A pressure gauge .140 and a normally open pressure switch 141 are located in the pipe 139 between the sequence valve 138 and the-cylinders 85, 85 and 85''.

The four-Way valve 121 may be of any usual and suitable construction of four-way valve adapted to be operated to one position by the solenoid 121-A to connect the oil pressure pipe 120 to the pipe 125, and the return pipe 124 to the pipe 129,'a11d to be operated to the other position by the solenoid 121-B to connect the pipe 120 to the pipe 129 and the return pipe 124 to the pipe 125.

With this construction, when the solenoid 121-A is energized the four-way valve is operated to position to admit oil under pressure to the cylinders 41, 78, 7 8' and 78 behind the pistons so astoextend the same and to connect the other end of the cylinders with the oil return line.

When the solenoid 121-B is energized .to operate the four-way valve 121 to the other position, oil under pressure is admitted to the cylinders 41 78, 78 and 78" in front of the pistons to retract the same while the other ends of these cylinders are then connected to the oil return line.

The four-way valve 134is of the same construction as the valve 121 and when operated to one position by the solenoid 1 34-A the oil pressure pipe 132 is connected to the pipe 136 and the oil return pipe .135 is connected to the pipe 137 and when opera-ted to the other position by the solenoid 134-B the pipes 132 and 137 are connected and the pipes 135 rand 136 are connected.

Thus, the solenoid 1.34-A is energized and the fourway valve 134 is operated to position to admit .oil to the main bending cylinder 43 behind the piston to extend the same and to discharge oil from the other end of this-cylinder to the reservoir, and when the solenoid 134B -is-energized the valve l-34 is operated to the other position to admit -oil under pressure to the cylinder 43 in front of the piston to retract the same and to discharge .oil from the other end of the cylinder to the reservoir.

In FIG. 20 is shown the pneumatic system for operating the pneumatic cylinders 100, 103 and 107 which control the movement of the slide members 5, '6 and 7 toward .and from each other. The motor operates the air compressor 151 which is connected by pipe 152 to the solenoid-operated four-way valve 153. A pipe .154 leads from the four-way valve 153 to a conventional two-way air valve or solenoid-operated shut-off valve 155 which is connected by pipe 156 to the pneumatic cylinder 100, behind the piston thereof.

A check valve 157 is located in the pipe 156 to permit flow therethrough only 'inthe direction of the arrow. A U-shape pipe 15-8is connectedat opposite ends to the pipe 156 on opposite sides of the check valve 157 and is provided witha check valve 159 permitting flow therethrough only in the direction of the arrow.

A flow control valve 160,-a regulator 161.and a pressure gauge 162 are located in the pipe 158. A pipe 163 connects the four-way valve 153 with a pipe 164 which leads through a solenoid-operated, two-way valve 165, similar to the valve 155, to the load end of thecylinder 100 and which leads through check valve 166, permitting flow only in the direction of the arrow to the pneumatic cylinder-107 behind the piston thereof.

A pipe 167 is connected at opposite ends .to the pipe 164, on opposite sides of the check valve 166, and has check valve 168 therein allowing flow only in the direction of the arrow. A pressure gauge 1'69' and relief valve 17 0 are also located in the-pipe 167.

A pipe 171 connects :the pipe 164 to the pneumatic cylinder 103 behind the piston thereofand has a check valve 172 therein permitting a flow only in the direction .ofthearrow. A pipe 173 istconnectedat opposite ends to the pipes .164 and 171, on opposite sides of the check valve 172 and has therein 'a check valve 174 (permitting how only in the direction of the arrow.

A pressure gauge175 and relief valve 176 are also located in the pipe 173. Both of thepneumatic cylinders 103 and 107 exhaust to the atmosphere at their loadends as indicated at 177 and 178.

The solenoid operated four way valve 153 may be of any usual and suitable construction of four-way valve adapted to be operated to one position by the solenoid 1'53-B-s0 as to connect the air pressure pipe 152 with the pipe 154 leading to the end of the pneumatic cylinder 1% behind the piston thereof, and operated to the other position by the solenoid 153-A to connect the pipe 152 to the pipe 163 and connect the pipe 154 with the exhaust 179 to atmosphere.

The two-way valve 155 is opened when the solenoid 155-1 thereof is energized and the two-way valve 165 is opened when the solenoid -1651 thereof is energized.

In FIG. 19 is shown an electric wiring diagram of the electrical devices which control the hydraulic and pneumatic mechanism which operates the apparatus. The power lines are indicated at and 186, a conventional start-stop main switch 187 being located in the line 185. Motors 115 and 150 for thehydraulic and pneumatic systems respectively are located in the main circuit and controlled by the main switch 187.

The normally open microswitches 188 and 189 on the slide member 7, as shown in FIGS. 1 and 2-, and located in the line 190'which is connected to the line wires 185 and 186. The solenoid 121-A of the four-way valve 121 of the hydraulic system shown in FIG. 21 is also located in the line 190.

A wire 191 connects the wires 1% and 1256, and the solenoid 153-B of the four way valve 15.3, of the pneumatic system shownin 'FIG. 20 isilocated in the Wire 15 1. A'shunt wire192is'connected to the wire 1%, around the microswitches 1 88 and 189 and provided with a push button or jog switch 193 adapted to be'rnanually operated to start 'thetfirst bending cycle of a tube passing out of the tube rolling mill.

Wire 194 is connected to 'the line wires 185 and 186 and passes through the solenoid 134-A of the four-way valve 134 of the hydraulic system shown in FIG. 21. The normally open microswitch 15,located on the slide 1 1 7 member 5, as shown in FIGS. 1 and 2, and the normally open pressure switch v196 are located in the wire i194.

A wire 197 is connected to the line wires 185 and 136 and passes through the solenoid 155-1 of the two-way valve 155 and the solenoid 165-1 of the two-way valve 165 of the pneumatic system shown in FIG. 20. The normally closed microswitch 198 shown in FIGS. 1 and 2 is located in the wire 197.

A conventional make-break switch (double poledouble throw) 2110 is interposed between the wires .194 and 197 and adapted to alternately make contact with the contact points ZMLA in the wire 194 and the contact points 206-13 in the wire 197. The make-break switch 262') is located on the slide member 6, as shown in FIGS. 1 and 2. As shown in FlG. 19, the make-break switch 206- is located in the wires 194 and 197 at a point between the microswitches 195 and 1% respectively and the line wire 185.

A wire 199 is connected at one end to the wire 167, between the make-break switch 200 and the microswitch 198, the other end of the wire 1% being connected to the line wire 186, through the solenoid 12'1B of the four-way valve 121 in the hydraulic system shown in FIG. 21.

The Wire 26 1 is connected to the wires 199 and 1 86 and passes through the solenoid 153-A of the four-way valve 153 in the pneumatic system shown in FIG. 2. A wire 2132 connects the wires 199 and 186 and passes through the solenoid 134-13 of the four-way valve 134 in the hydraulic system shown in FIG. 21.

In the operation of the machine, in order to make the first bend in a tube just emerging from the tube mill 13, after the main switch 187 is closed, the jog switch 193 is operated manually. This is the only time during the operation of the machine that this jog switch is used.

Assuming the slides 5, 6 and 7 to be separated in the starting position, as in FIG. 1, when the leading end of the tube reaches the first holding and setting dies indicated generally at 59, on the third slide 7, the jog switch 193 is manually closed to form the first bend in the tube 14.

Upon closing of the jog switch, the electric circuit shown in FIG. 19 will function to actuate the hydraulic and pneumatic cylinders to operate the apparatus. The tube will be clamped at spaced points by the clamping dies lei-17 on the first slide members 5, and by the first upper holding and die means 5? on the third slide 7.

Then, the bending die 49 on the second slide member 6, will be moved downward engaging the tube at a point midway between the first and third slide members 5 and 7 respectively, bending the tube into V-shape. The tube will be under tension during this bending operation, owing to resistance of the pneumatic cylinders 193 and 167 to lateral movement of the slide members 5 and 7 toward the intermediate slide member 6. This results in stretch bending of the tube or bar, stretching it around the bending die 49 as it is bent and thus tending to set the V-shape bend in the tube.

After the first bend has been formed in the tube, and the slides 5, 6 and 7 have returned to the starting position, at this time all of the hydraulic cylinders 4 1, 43, 7'8, 78', 7'8", 85, 85 and 85" are in retracted position and the pneumatic cylinders 103 and 1117 are extended and the pneumatic cylinder 1% is retracted, by virtue of air pressure trapped in the pneumatic system.

The tube or bar 14 moves to the right, as viewed in FIGS. 1 and 2, until the previously formed bend therein contacts the normally open microswitches 188 and 189 which are wired in series as shown in FlG. 19. These rnicroswitches 18% and 189- will thus be closed by the moving tube, closing the circuit through the Wire 1911 and energizing the solenoid 121-A of the four-way valve 121 in the hydraulic circuit.

At the same time the circuit is simultaneously closed through the wire 191 which energizes the solenoid 153-8 of the four-wav'valve 153 in the pneumatic circuit. The operation of the hydraulic system is thus started. The piston rods 77, 77 and 77" of the cylinders 78, 78' and V 12 V 78" respectively start to extend and at the same time the piston rod 41 of the hydraulic cylinder 41 starts to extend.

Through the toggle levers 33 and 34 the hydraulic cylinder 41 will clamp the tube between the clamping dies 16 and 17 and raise the circular die 26 to contact with the tube. Through the toggle levers 69, 69 and 69" the hydraulic cylinders 78, 78 and 78" will lower the setting dies 61 and 61 and raise the setting die 61 into contact with the previously formed bends in the tube.

When the pistons of these four hydraulic cylinders are locked in place, the sequence valve 138 in the hydraulic system will open and the pistons of the hydraulic cylinders 85, and 85 will be extended and through the levers $8, 88 and 83", the rollers 82, 82' and $2" and cam plates 83, 83 and 83 will move the circular holding and setting dies 62 and 62 forward and upward and the circular holding and setting die 62" forward and downward clamping the previously bent portions of the tube or bar in the clamping and setting dies to set the bends therein.

Since the lower setting die 62 is located a slightly greater distance from the upper setting dies 62 and 62' than the distance from the bending die 49 from the dies 26 and 62 at the end of the bending operation, the tube or rod will be further stretched in the setting operation. The spacing of the setting dies is such that the metal will be stretched slightly beyond the yield point, whereby the bends in the tube or bar will be positively set.

The normally open microswitch 195 has been closed at this time by the chuck on the first slide member 5 activated through the hydraulic cylinder 41. After these hydraulic cylinders are locked in extended position, the normally open pressure switch 196 closes, closing the circuit through the wire 194 and energizing the solenoid 134A of the four-way valve 134 in the hydraulic system.

Liquid under pressure is thus admitted to the main bending cylinder 43, behind or above the piston thereof, extending the piston rod 45 thereof downward so that the bending die 49 starts to bend the tube downwardly between the circular dies 26 and 62.

Closing of the microswitch 195 closes the circuit through the wire 197, energizing the solenoids -1 and 1654 of the two-way valves 155 and respectively of the pneumatic system, opening these two-way valves to extend the piston of the pneumatic cylinder 111i) and starts pushing the first slide member 5 to the right, as viewed in FIGS. 1 and 2, thus creating tension on the tube or bar which is clamped in the apparatus as above described.

At the same time, pressure is relieved from the load ends of the pneumatic cylinders 103 and 167. The slide members 6 and 7 are held at the proper distance from each other and from the slide member 5 by the tubing or bar clamped in the dies on these slides, as above described.

Force on the pneumatic cylinder 100 is controlled by means of the by-pass and check valves 157 and 159 of the pneumatic system. Flow through the by-pass is controlled by the flow control valve 160, regulator valve 161 and gauge 162.

The cylinders 103 and 107 are pushed together by the bending action of the tubing or bar produced by the bending die 49 operated by the main bending cylinder 43. Resistance to the slide members 5, 6 and 7 moving together is controlled by the by-pass and check valves 172, 174, 168 and 166. Flow through the by-pass is controlled by the flow control valves 176 and 170 and pressure gauges and 169 of the pneumatic system.

When the piston of the main bending cylinder 43 reaches the desired degree of bend, the make-break switch 26-9 on the slide member 6 is contacted and the solenoid 121-13 of the four-way valve 121 of the hydraulic system, the solenoid 153-A of the four-way valve 153 of the pneumatic system, and the solenoid 134-B of the four- :13 way, valve 134 of the hydraulic system, will be energized, operating the tour-way valves .121, 153 and 134 to the reverse position, and all of the cylinders will be returned to. starting position.

The slide members.5, 6 and 7 will be returned to starting position, and when the slide member contacts the normally closedmicroswitch .198 thesolenoids 155-1 and 165-1 of the two-way valves 155 and.165 respectively of theipneumatic system will be deenergized locking the piston of the pneumatic cylinder 100 and theslidetmembers 5,.6and 7 in starting position.

As all of .the hydraulic cylinders are .thus retracted, theclamping dies upon .theslide member 5 and the holding and setting dies on slide member 7 are thus moved out of the path of the tube, and as the .tube continues to-move from the tube mill through the apparatus, this operation will be continuously repeated automatically every timela previously formed'bend in thetube contacts the .microswitches 188 and 189' repeating the operation as above described.

It willbe-obvious from the above disclosure that in the bending operation, the tube is under tension and is being stretched around the die 49 into the V-shape. This is an important feature of theapparatus-and this stretch bendingot-the tube is producedby resistanceof-the pneumatic cylinders .103 and 107 to lateral movement of slides 5 and 7 toward slide "6.

Furthermore, :it will be seen that the previously bent tube or bar is further stretched in the setting operation. This -is accomplished by locating the lower setting die 62"wso as to stretch the metal slightly beyond the yield point.

In the foregoing description, certain terms have been used for brevity, clearness and under-standing, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for descriptive purposes herein and are intended to be broadly construed.

Moreover, the embodiments of the improved construction illustrated and described herein are by way of example, and the scope of the present invention is not limited to the exact details .of construction.

Having now described the invention or discovery, the construction, the operation, and use of preferredembodiments thereof, and the advantageous new and useful results obtained thereby; the new and useful construction, and reasonable mechanical equivalents thereof obvious .to those skilled .in the art, are set forth in theappended claims.

I claim:

1. Tube and bar bending apparatus comprising means for continuously moving a tube and the like longitudinally therethrough, a pair of dies spaced longitudinally in the path of the moving tube, tube-clamping means associated with each of said dies, a third die located between said pair of diesand movabletransversely across the path of said tube, each of said .pair of dies and said third die being .movable toward and fromeach other longitudinally of the path of the moving tube, and means actuated by the movement of the tube for operating said clamping means and moving said third dieperpendicular to the path of the tube to continuously form successive V-shaped bends in the continuously moving tube.

2. Tube and bar bending apparatus comprising means for continuously moving a tube and the like longitudinally therethrough, a first bending die located at one side of the path of the moving tube, a second bending die located beyond said first die at the other side of the path of the tube and movable transversely across the path of the tube, a series of holding and setting dies located beyond said second bending die, all of said bending dies and said series of holding and setting dies being movable toward and from each other longitudinally of the path of the moving tube, tube-clamping means associated with said first bending die and with said holding and setting 914 dies, and means for operating said clamping means and moving said second bending dieperpendicular to thepath of the tube to continuously form successive V-shaped bends in the continuously moving tube and to simultaneously set previously formed bends in the tube.

3. Tubeand bar bendingapparatus comprising means forcontinuously movinga tube and the like longitudinally therethrough, a first bending die located at one side of the path of the moving tube, a second bendingdie located beyond said firstdieatthe other side of the .path ofthe tube and movable transversely across the path of the tube, .aseries of holdingand setting dies located beyond said second bending die, each of said bending dies and said series of holding and setting dies being movable toward and from each other longitudinally ofthe path of the .moving tube, each ofsaid bending dies and holdingand setting dieshaving a circular tube-receiving. groove therein, tube-clamping means associated with said first bending die and withsaid holding and setting .dies, and means for operating said clamping means and moving said second bending die perpendicular to the .tube .to continuously form successive Vashaped bends in the -con tinuously moving tube and to simultaneously set previouslyiformed bends in the tube.

4. Tube and bar bending'apparatus comprising .means forcontinuously moving a tube and the like longitudinally therethrough, said apparatus comprising .a frame, first, second and third slide members upon said frame, all of said slide members being movable upon .theframe toward and from each other longitudinally of the path of the moving tube, tube-clamping dies on the first slide member, a first bending die located on said first slide member beyond .theclamping die and at one side of the path of the moving tube, means for movingsaid clamping dies and bendingdie into and out of contact with the tube, a main bending-die located on the :second slide "member at the other side-of the path of the moving tube, means for moving the main bending die transversely across the path of the tube for forming V -shaped bends therein, holding andsetting die means on the third slide member forsetting bends, formed in the tube by the bending dies, said holding and setting die means comprising a plurality of dies for contacting the outer sides of bends in the tube, means for moving said last named dies into and out of contact with the outer sides of the bends in the tube, a plurality of dies for contacting the :inner sides of the bends in the tube, means for moving the last named dies diagonally into and out of the path of the bent portion of the tube, and means actuated by the moving tube for operating said apparatus for continuously forming sue cessive V-shaped bends in the tube and simultaneously setting previously formed-bends in the tube.

5. Tubetand bar bending-apparatus as defined in claim 4, in which the clamping dies on the first slide member remain in clamping :position until after said first bending die is moved outof contact with the tube.

6. Tube and bar bending apparatus as defined in claim 4, in which the means for moving each of the dies is operated by hydraulic cylinder means.

7. Tube and bar bending apparatus as defined in claim 6 in which the operation of the hydraulic cylinder means is controlled by means actuated by the moving tube.

8. Tube and bar bending apparatus 'as'defined in claim 6, in which the operation of the hydraulic cylinder means to extended position is initiated by means on the third slide member actuated by the moving tube and in which the operation of the hydraulic cylinder means to a retracted position is initiated by means on the second slide member actuated by the movement of the main bending die.

9. Tube and bar bending apparatus as defined in claim 4, in which the means for moving the last named dies diagonally into and out of the bent portion of the tube 5 includes cam plates mounted on the third slide member and having cam slots therein and rollers upon said dies located in said cam plates.

10. Tube and bar bending apparatus comprising means for continuously moving a tube and the like longitudinally therethrough, said apparatus including a frame, first, second and third slide members each movable on the frame toward and from each other longitudinally of the path of the tube, tube-clamping means on the first slide member, tube-bending means on the second slide member, bendsetting means on the third slide member, means actuated by the movement of the tube for operating said clamping, bending and setting means for continuously forming successive V-shaped bends in the tube and setting said bends, and pneumatic cylinder means for controlling the movement of said slide members toward and from each other, said pneumatic cylinder means comprising a cylinder mounted on the frame and having a piston rod connected to the first slide member, a cylinder mounted on the first slide member and having a piston rod connected to the second slide member and a cylinder mounted on the second slide member and having a piston rod connected to the third slide member, and means actuated by the moving tube for operating said cylinders.

11. Tube and bar bending apparatus comprising means for continuously moving a tube and the like longitudinally therethrough, said apparatus including a frame, first, second and third slide members each movable on the frame toward and from each other longitudinally of the path of the tube, tube-clamping means on the first slide member, tube-bending means on the second slide member, bendsetting means on the third slide member, means actuated by the movement of the tube for operating said clamping, bending and setting means for continuously forming successive V-shaped bends in the tube and setting said bends, and pneumatic cylinder means for controlling the movement of said slide members toward and from each other, said pneumatic cylinder means comprising a cylinder mounted on the frame and having a piston rod connected to the first slide member, a cylinder mounted on the first slide member and having a piston rod connected to the second slide member and a cylinder mounted on the second slide member and having a piston rod connected to the third slide member, means actuated by the moving tube for operating said cylinders, and means upon the frame actuated by the movement of the first slide member for controlling the operation of the cylinder-operating means for returning the slides to starting position after each operation of the clamping, bending and setting means.

12. Tube bending apparatus comprising means for moving a tube longitudinally therethrough, a pair of dies spaced longitudinally at one sideof the path of the tube, each of said dies being of substantially cylindrical shape and having a peripheral groove therein to receive the tube, tube-clamping means associated With each of said 13. Tube bending apparatus comprising means for moving a tube longitudinally therethrough, said apparatus comprising a frame, first, second and third slide members movable upon said frame toward and from each other longitudinally of the path of the tube, tube-clamping dies located on said first slide member, a first bending die located on said first slide member at one side of the path of the tube, a main bending die located on said second slide member at the other side of the path of the tube, said first bending die and said main bending die each being of substantially cylindrical shape and having a peripheral groove therein to receive the tube, means for moving said main bending die transversely across the path of the tube for forming V-shaped bends therein, holding and setting die means on said third slide member for setting bends formed in the tube by said bending dies, said holding and setting die means comprising a plurality of dies having arcuate grooves therein for contacting the outer sides of the bends in the tube, and a plurality of substantially cylindrical dies having peripheral grooves therein for contacting the inner sides of the bends in the tube, and means for moving said holding and setting die means into and out of contact with the bends in the tube.

14. Tube bending apparatus comprising means for moving a tube longitudinally therethrough, said apparatus comprising first, second and third slide members movable toward and from each other longitudinally of the path of the tube, tube-clamping means on said first slide member, a first bending die on said first slide member at one side of the path of the tube, a main bending die on said second slide member at the other side of the path of the tube, means for moving the main bending die transversely across the path of the tube in a path perpendicular to the tube for forming V-shaped bends in the tube, holding and setting means on said third slide member for setting bends formed in the tube by the bending dies, said holding and setting means comprising a plurality of dies for contacting the outer sides of bends in the tube, means for moving said last named dies into and out of contact With the outer sides of bends in the tube, a plurality of dies for contacting the inner sides of bends in the tube, and means for moving said last named dies into contact with the inner sides of bends in the tube and out of the. path of the bent portion of the tube.

15. Tube bending apparatus as defined in claim 14, in which the bending dies and the dies for contacting the inner sides of bends in the tube are each of substantially cylindrical shape having a peripheral groove therein for receiving the tube, and said dies for contacting the outer sides of bends in the tube each has an arcuate groove therein for receiving the tube.

References Cited in the file of this patent UNITED STATES PATENTS 1,867,581 Marietta July 19, 1932 2,437,092 Greene et al Mar. 2, 1948 2,485,282 Green Oct. 18, 1949 FOREIGN PATENTS 207,721 Australia Apr. 10, 1957 

1. TUBE AND BAR BENDING APPARATUS COMPRISING MEANS FOR CONTINUOUSLY MOVING A TUBE AND THE LIKE LONGITUDINALLY THERETHROUGH, A PAIR OF DIES SPACED LONGITUDINALLY IN THE PATH OF THE MOVING TUBE, TUBE-CLAMPING MEANS ASSOCIATED WITH EACH OF SAID DIES, A THIRD DIE LOCATED BETWEEN SAID PAIR OF DIES AND MOVABLE TRANSVERSELY ACROSS THE PATH OF SAID TUBE, EACH OF SAID PAIR OF DIES AND SAID THIRD DIE BEING MOVABLE TOWARD AND FROM EACH OTHER LONGITUDINALLY OF THE PATH OF THE MOVING TUBE, AND MEANS ACTUATED BY THE MOVEMENT OF THE TUBE FOR OPERATING SAID CLAMPING MEANS AND MOVING SAID THIRD DIE PERPENDICULAR TO THE PATH OF THE TUBE TO CONTINUOUSLY FORM SUCCESSIVE V-SHAPED BENDS IN THE CONTINUOUSLY MOVING TUBE. 